ab - Apache HTTP server benchmarking tool

ab is a tool for benchmarking your Apache Hypertext
Transfer Protocol (HTTP) server. It is designed to give you an impression
of how your current Apache installation performs. This especially shows
you how many requests per second your Apache installation is capable of
serving.

Supply BASIC Authentication credentials to the server. The username and
password are separated by a single : and sent on the wire
base64 encoded. The string is sent regardless of whether the server needs
it (i.e., has sent an 401 authentication needed).

-b windowsize

Size of TCP send/receive buffer, in bytes.

-B local-address

Address to bind to when making outgoing connections.

-c concurrency

Number of multiple requests to perform at a time. Default is one
request at a time.

-C cookie-name=value

Add a Cookie: line to the request. The argument is
typically in the form of a name=value
pair. This field is repeatable.

-d

Do not display the "percentage served within XX [ms] table". (legacy
support).

-e csv-file

Write a Comma separated value (CSV) file which contains for each
percentage (from 1% to 100%) the time (in milliseconds) it took to serve
that percentage of the requests. This is usually more useful than the
'gnuplot' file; as the results are already 'binned'.

-f protocol

Specify SSL/TLS protocol (SSL2, SSL3, TLS1, TLS1.1, TLS1.2, or ALL).
TLS1.1 and TLS1.2 support available in 2.4.4 and later.

-g gnuplot-file

Write all measured values out as a 'gnuplot' or TSV (Tab separate
values) file. This file can easily be imported into packages like Gnuplot,
IDL, Mathematica, Igor or even Excel. The labels are on the first line of
the file.

-h

Display usage information.

-H custom-header

Append extra headers to the request. The argument is typically in
the form of a valid header line, containing a colon-separated field-value
pair (i.e., "Accept-Encoding: zip/zop;8bit").

Do not report errors if the length of the responses is not constant. This
can be usefull for dynamic pages.
Available in 2.4.7 and later.

-m HTTP-method

Custom HTTP method for the requests.
Available in 2.4.10 and later.

-n requests

Number of requests to perform for the benchmarking session. The default
is to just perform a single request which usually leads to
non-representative benchmarking results.

-p POST-file

File containing data to POST. Remember to also set -T.

-P proxy-auth-username:password

Supply BASIC Authentication credentials to a proxy en-route. The
username and password are separated by a single : and sent on
the wire base64 encoded. The string is sent regardless of whether the
proxy needs it (i.e., has sent an 407 proxy authentication
needed).

-q

When processing more than 150 requests, ab outputs a
progress count on stderr every 10% or 100 requests or so. The
-q flag will suppress these messages.

-r

Don't exit on socket receive errors.

-s timeout

Maximum number of seconds to wait before the socket times out.
Default is 30 seconds.
Available in 2.4.4 and later.

-S

Do not display the median and standard deviation values, nor display
the warning/error messages when the average and median are more than
one or two times the standard deviation apart. And default to the
min/avg/max values. (legacy support).

-t timelimit

Maximum number of seconds to spend for benchmarking. This implies a
-n 50000 internally. Use this to benchmark the server within a
fixed total amount of time. Per default there is no timelimit.

-T content-type

Content-type header to use for POST/PUT data, eg.
application/x-www-form-urlencoded.
Default is text/plain.

The value, if any, returned in the server HTTP header
of the first successful response. This includes all characters in the
header from beginning to the point a character with decimal value of 32
(most notably: a space or CR/LF) is detected.

Server Hostname

The DNS or IP address given on the command line

Server Port

The port to which ab is connecting. If no port is given on the
command line, this will default to 80 for http and 443 for
https.

SSL/TLS Protocol

The protocol parameters negotiated between the client and server.
This will only be printed if SSL is used.

Document Path

The request URI parsed from the command line string.

Document Length

This is the size in bytes of the first successfully returned document.
If the document length changes during testing, the response is
considered an error.

Concurrency Level

The number of concurrent clients used during the test

Time taken for tests

This is the time taken from the moment the first socket connection
is created to the moment the last response is received

Complete requests

The number of successful responses received

Failed requests

The number of requests that were considered a failure. If the
number is greater than zero, another line will be printed showing the
number of requests that failed due to connecting, reading, incorrect
content length, or exceptions.

Write errors

The number of errors that failed during write (broken pipe).

Non-2xx responses

The number of responses that were not in the 200 series of response
codes. If all responses were 200, this field is not printed.

Keep-Alive requests

The number of connections that resulted in Keep-Alive requests

Total body sent

If configured to send data as part of the test, this is the total
number of bytes sent during the tests. This field is omitted if the test
did not include a body to send.

Total transferred

The total number of bytes received from the server. This number
is essentially the number of bytes sent over the wire.

HTML transferred

The total number of document bytes received from the server. This
number excludes bytes received in HTTP headers

Requests per second

This is the number of requests per second. This value is the result
of dividing the number of requests by the total time taken

Time per request

The average time spent per request. The first value is calculated
with the formula concurrency * timetaken * 1000 / done
while the second value is calculated with the formula
timetaken * 1000 / done

Transfer rate

The rate of transfer as calculated by the formula
totalread / 1024 / timetaken

There are various statically declared buffers of fixed length. Combined
with the lazy parsing of the command line arguments, the response headers
from the server and other external inputs, this might bite you.

It does not implement HTTP/1.x fully; only accepts some 'expected' forms
of responses. The rather heavy use of strstr(3) shows up top
in profile, which might indicate a performance problem; i.e., you
would measure the ab performance rather than the server's.

Notice:This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.